The present subject matter relates to the fields of peptide and polypeptide selection, immunology, and targeted contraception in animals. In particular, the present subject matter relates to peptides and polypeptides that bind to the zona pellucida (ZP) of oocytes, methods for selecting such peptides and polypeptides, vectors that express the selected peptides and polypeptides, and compositions that comprise such peptides, polypeptides, or vectors (e.g., compositions for inducing an immune response against sperm).
Overpopulation of animals of multiple species including domestic, feral, and wild animals results in various economic, health, and security problems. For example, feral swine cause significant physical damage to agricultural crops, soils, vineyards, tree plantings, turf, rare plant communities, wildlife habitat, archaeological sites, and vehicles. (See Ditchkoff S S, West B C. Ecology and management of feral hogs. Human-Wildlife Conflicts 2007; 1(2): 149-151). Feral swine compete with livestock and native wildlife for food, and prey on domestic animals and wildlife. Feral swine carry at least thirty important viral and bacterial diseases and thirty-seven parasites that affect humans, pets, livestock, and wildlife (e.g., brucellosis, salmonellosis, diseases due to pathogenic E. coli strains, rabies, tuberculosis, and tularemia). Feral swine also could potentially spread additional human and animal diseases not currently found in the United States. (See Hutton T, DeLiberto T, Owen S, Morrison B. Disease risks associated with increasing feral swine numbers and distribution in the United States. Midwest Association of Fish and Wildlilfe Agencies 2006). Control programs for feral swine eradication such as poisoning, trapping, shooting, etc., are ineffective, expensive and generally unacceptable to the public. Currently available contraceptives for animals are not selective and affect multiple species and, therefore, cannot be permitted for use in uncontrolled environments such as natural habitats of feral or wild animals. (See Miller L A, Johns B E, Killian G J. Immunocontraception of white-tailed deer with GnRH vaccine. Am J Reprod Immunol 2000; 44(5):266-274; and Killian G, Miller L, Rhyan J, Doten H. Immunocontraception of Florida feral swine with a single-dose GnRH vaccine. American Journal of Reproductive Immunology 2006; 55:378-384). Thus, there is an urgent need for immunocontraceptive, species-specific vaccines that can affect the target species only and be delivered via economically sound oral or oronasal administration. Additional examples of species, the overpopulation of which imposes various kinds of economic and health risks, include coyotes, deer, and raccoons.